DE 198 60 154 A1 describes a crankcase ventilation device via which the cleaned blow-by gases are returned from the crankcase of an internal combustion engine into the intake tract. The crankcase ventilation device features in a housing through which leads a flow path for the blow-by gases, a pressure regulating valve which, depending on the differential pressure, switches upstream and downstream of the valve between an opening and closing position. The pressure regulating valve of which is designed mechanically and features as valve body a membrane which is pretensioned into the opening position by a spring element.
JP 2010-196594 A describes a crankcase ventilation device which features an electro-magnetic closing valve that is switched depending on the pressure by supplying current to a coil. The pressure is determined by means of a pressure sensor.